SPOKANE, Wash. -- Plenty of farmers and others in Washington state love the idea of growing crops to make clean-burning vehicle fuels to cut pollution and the nation's reliance on foreign oil.

The trick is to make producing "biodiesel" profitable. Now, the state Legislature is considering a bill that would provide incentives to increase the production and use of alternative fuel in the state.

"The issue is resonating well with legislators," said Clifford Traisman, a lobbyist for the Washington Environmental Council and other groups pushing the measure.

The incentives would go to farmers to grow crops like canola, and to various government entities to replace or retrofit big polluters like school buses.

Biodiesel is a clean-burning alternative fuel made from oils derived from farm crops, and can be used in any conventional diesel engine. It is used in pure form or blended with regular diesel.

Besides fighting global warming, biofuel could provide an economic boost to farmers if the new crops can be sold for high prices, Traisman said. He said the "clean air, clean fuels" bill has 36 sponsors in the House.

The bill proposes spending $20 million on a variety of incentives. A key provision is $5 million for local governments to replace 700 aging diesel school buses with newer models. It also provides money to retrofit other buses so they run more cleanly.

The bill would encourage the creation of biofuels production plants.

A Seattle company called Imperium Renewables Inc. is already building an enormous biodiesel plant between Aberdeen and Hoquiam. Another plant is under consideration in Ellensburg by a company called Central Washington Biodiesel. Seattle Biodiesel already operates the Northwest's first commercial refinery.

The measure would allow the state to contract with fuel producers to purchase their product for the state motor fleet and allow public utilities to produce and distribute biofuels created from Washington state products.

The bill would also require the state to reduce its fossil fuel use by 25 percent below 2006 levels by the year 2020.

Under the measure, the state would use $500,000 to help create ethanol fueling stations along the Interstate 5 and Interstate 90 corridors. Another $6.75 million would go to Washington State University's energy program to qualify for federal matching dollars for research.

Major users of biodiesel in Washington could be state ferries, transit buses, school buses and many farm vehicles. A measure being considered in the state Senate would exempt biodiesel fuel used for non-highway farm use from sales and use taxes.

The bills are intended to complement previous state law calling for 2 percent of the motor fuel sold in Washington to be from renewable sources, said Tom Geiger, a spokesman for the environmental council.

There are some concerns, however.

Some farmers worry they will not make any money if they undertake the expense of converting to production of canola. Processing plants have also been slow to break ground.

Glen Squires, vice president of the Washington Wheat Commission, said many of the state's 2.2 million acres of wheat fields are not suitable for canola. Farmers are also wary because they cannot get insurance for growing canola and fear being left holding a crop they cannot sell, he said.

"Wheat they have a market for," Squires said.

Still, the bill received plenty of support from various interest groups at a hearing Wednesday of the state House Agriculture and Natural Resources Committee in Olympia.

Fred Fleming, a fourth generation wheat farmer from Reardan, is involved in efforts to boost the production of biodiesel. He said the biofuels industry offers huge potential for farmers to diversify.

"For a change in agriculture, the future is finally starting to look bright," Fleming said.